Method of producing a base plate having a groove with a coil spring mounted therein



Dec.'24, 1968 A. EINFALT 3,413,410

' METHOD OF PRODUCING A BASE PLATE HAVING A GROOVE WITH A COIL SPRING MOUNTED THEREIN Filed Aug. 5, 1966 lNV-ENTOR 3 uncut. Emrnur QMAMAQL humans United States Patent "i 3,418,410

Patented Dec. 24, 1968 taining the screw springs, that only a narrow, upwards METHO OF PRoafi f gg A BASE PL opening slot is present, so that the springs cannot jump out of their seating, which they would tend to do when HAVING A GROOVE WITH A 'COIL SPRING THE they are driven. Another advantage resides m that this Alfre ii li gl tPN umber g rmany, assignor to Gebruder 5 form. the i or Slots be achieve! withciu't Ei f lt Blechspielwarenfabrik, Numberg, Germany a requrrmg addit onal components such as covering StI'IPS German firm or the like, which would have to be made separately, to

Filed Aug. 3, 1966, Ser. No. 569,860 be fastened subsequently to the base plate. Claims priority, application Ggrmany, Feb. 14, 196 It is of course possible to have the pressing process,

E 31,04 10 in the course of which the elevated wall portions of the 3 Chums 264-242) grooves are bent inwardly, follow immediately the drawing process during which the base plates are shaped.

The accompanying drawing illustrates the invention ABSTRACT OF THE DISCLOSURE schematically, with reference to an exemplary embodi- There is disclosed a base plate having in one side a merit.

groove constituting a track for toy vehicles. A coil spring FIG. 1 shows a top view of a base plate, provided only rotatably fitted into the groove and engageable by the with an oval track, for a toy vehicle set;

catch member or driver depending from a toy vehicle FIG. 2 is a partial section on an enlarged scale, after drives the engaged vehicle along the track when the completion of the drawing process; and

spring is rotated by some suitable driving device such FIG. 3 shows the same partial section on an enlarged as a small electric motor. The cross-sectional peripheral scale after completion of the pressing process,

outline of the track groove is such that the width of The base plate a, which is advantageously formed from the mouth of the groove is narrower than the maximal a sheet of plastics material by deep drawing for example, diameter of the spring so that the same is safely held has in the example of embodimtnt here shown only an captive in the groove. There is also disclosed a method oval track, in the center of which a recessed slot [2 is of producing the track groove in an economic fashion. located, accommodating a screw spring 0, which is rotatable by some suitable means, e.g. a miniature electric motor and which thereby entrains a driver projecting thereinto from the toy vehicles, said drivers being formed in the usual manner as thin pins.

As already mentioned, the screw spring tends to jump out of its slot in upward direction, if the aperture of the This invention relates to a method of producing play sets with toy vehicles, comprising a base provided with at least one track on which the toy vehicles may move,

said vehicles being propelled by means of a rotatable Screw or core Spring, Sunk into the track and engaged latter corresponds to its internal diameter. The r1sk of I the screw springs leaving their grooves arises especially 32 323 of catch elemmts depmdmg from the my 35 when the direction of travel is reversed, or when the rotational speed of the spring is changed. For this reason, the slot must have an opening in the form of a narrow slot d.

This is achieved according to the invention by forming during the deep drawing of the base plate a, the slotshaped recess e so that its flanks f project above the plane of the base plate, thus forming upward-projecting end portions or lips g extending along the slots.

In such toy vehicle sets, the screw springs are usually located in recessed grooves or slots in the base plates on which the tracks are formed. The screw springs must be given a good guidance in their grooves or slots so that they will remain in their position of use in spite of their continuous rotation changes in speed, and reversal. This is especially important at those points where the tracks curve. For this reason the grooves accom- I bent mmodatmg the screw springs must not only open upwards, These end Pomons g of i flanks are then 311: must h e omy a natgrowgsllot lat thehtop rei agve m 40 g i g g g g gg gg z g fgf flf gg eir intern iameter, rou w ich t e pin-i e e ee ments of the vehicles can engage said screw springs. Tg 1 i located approximately Difiiculties are encountered when trying to satisfy these Zy 223 i z i g aperture of the 510 t d requirements, especially when the base plate, together We and to e $5352.22th trih l iiiffi 232553111? from synthetic plastics materials by the deep drawmg b more i 180 th w a the recess in which method, in order to exploit the advantages mherent to 1 t d y e a both the plastics material and the method in question. n i 9 This problem is solved according to the present incalm vention in that the plastics material base plate accorn- A method of producmg a base Plate havmg m one modating the track(s) is provided with slot-shaped recess of its sides, a 9? groove for toy vehiclfis, into ii for containing a screw spring which surrounds its screw 52 53 fi s im: igg g g i g g gi $5 2 33; spring by more than 180 and has an upwards-opening i g g the Stags. y g slot.

- forming in a base plate an elongate groove having In the manufacture of a base plate of this kll'ld for a l toy vehicle set described at the outset, the process adopted i gi g gigg i g g i j o i z ggz l r ggtggl will be preferably one whereln the plate is provided, for therein and havino a diameter less than z maxim a1 example in the course of deepadrawmg, with a sem1- depth of the i and cylindrical recess flanks of which pro ect slightly above turning said u p8 inwardly across the mouth of the the plate surface, whereafter the upwardly-projecting end v groove to reduce the width of the mouth to a width portions of the flanks are bent inwards towards one anless than the diameter of the coil Spring thereby other, for instance by a pressing process, so as to leave holding the Same captive in the groove free the aforementioned slot, through which the catch 2 In the h d according to claim 1 h Steps f el of the y Vehicles can extendinitially forming said groove with a semi-spherical cross- The progress otfered by the in e that t sectional outline at its base upwardly continuedby straight grooveor slot-shaped recesses are so formed for conwall portions into said protruding lips, and then turning said lips and the contiguous straight wall portions into a configuration such that the final peripheral crosssectional outline of the groove is substantially circular and the lips are flush with said side of the base plate.

3. In the method according to claim- 1 the step of forming said base plate of thermo-plastic material as a onepiece structure.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 5/1963 Canada.

10 CHARLIE T. MOON, Primary Examiner.

U.S. Cl. X.R. 

